Immediate and Long-term Results Following Balloon Mitral Valvotomy in Patients With Atrial Fibrillation

Authors

  • Krishna Kumar Mohanan Nair MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Harikrishnan Sivadasan Pillai MD, FACC,

    Corresponding author
    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
    • Department of Cardiology. Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India 695011
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  • Anees Thajudeen MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Kavassery Mahadevan Krishnamoorthy MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Sivasankaran Sivasubramonian MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Narayanan Namboodiri MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Bijulal Sasidharan MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Sanjay Ganapathy MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Ajitkumar Varaparambil MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Thomas Titus MD,

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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  • Jaganmohan Tharakan MD

    1. Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
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Abstract

Background:

The purpose of this study was to examine the influence of atrial fibrillation (AF) on the immediate and long-term outcome of patients undergoing balloon mitral valvotomy (BMV).

Hypothesis:

Patients with atrial fibrillation fair poorly after balloon mitral valvotomy.

Methods:

There were a total of 818 consecutive patients who underwent elective BMV in this institute from 1997 to 2003, with either double-lumen or triple-lumen BMV catheters included in the study. Of them, 95 were with AF. The clinical, echocardiographic, and hemodynamic data of these patients were compared with those of 723 patients in normal sinus rhythm (NSR). Immediate procedural results and long-term events were compared between the 2 study groups.

Results:

Patients with AF were older (39.9 ± 9.9 years vs 29.4 ± 10.1, P < 0.001) and presented more frequently with New York Heart Association (NYHA) class III-IV (53.7% vs 32.9%, P < 0.001), echocardiographic score >8 (47.4% vs 24.9%, P < 0.001), and with history of previous surgical commissurotomy (33.7% vs 11.5%, P < 0.001). In patients with AF, BMV resulted in inferior immediate and long-term outcomes, as reflected in a lesser post-BMV mitral valve area (1.3 ± 0.4 vs 1.6 ± 0.4 cm2, P = 0.032) and higher event rate on follow-up.

Conclusions:

Patients with AF were older, sicker, and had advanced rheumatic mitral valve disease. They had a higher incidence of stroke, new onset heart failure, and need for reinterventions on long-term follow-up. These patients need intense and more frequent follow-up. Clin. Cardiol. 2011 DOI: 10.1002/clc.22068

The authors have no funding, financial relationships, or conflicts of interest to disclose.

Introduction

In the treatment of patients with symptomatic mitral stenosis, balloon mitral valvotomy (BMV) has been established as an alternative to surgical mitral commissurotomy.1–12 Atrial fibrillation (AF) is an important and common cardiac arrhythmia in patients with mitral stenosis, and is associated with hemodynamic and clinical decompensation. Previous surgical studies have demonstrated that the presence of AF is associated with suboptimal immediate and long-term outcome after surgical mitral commissurotomy.13–19 However, studies addressing the issue on patients after balloon mitral valvotomy are scarce. Thus, the purpose of this study was to address this important clinical issue by evaluating the effect of AF on the immediate and long-term outcome of BMV in a large cohort of consecutive patients undergoing the procedure.

Methods

Study Population

Clinical, echocardiographic, and hemodynamic data of 818 consecutive patients who underwent BMV in our institute from 1997 to 2003 were analyzed retrospectively. The clinical, echocardiographic, and hemodynamic data of 95 patients with AF were compared to the data of 723 patients with normal sinus rhythm (NSR). BMVs that were done as emergency procedures under mechanical ventilation were excluded.

Procedure

All patients had a detailed clinical and echocardiographic (2-dimensional echo, Doppler, and color flow imaging) evaluation, to assess the severity of mitral stenosis, valve morphology, and mitral regurgitation (MR). The Wilkins echocardiographic scoring system17 was used to assess the severity of mitral valve thickness, leaflet mobility, valvular calcification, and subvalvular disease, each being graded from 1 to 4 to a maximum score of 16.

The mitral valve area was determined by 2-dimensional echocardiography with planimetry in the parasternal short-axis view and by continuous-wave Doppler using the pressure half-time method. Transesophageal echocardiography (TEE) was routinely done. Transthoracic echocardiogram was done during BMV, 24 hours after the procedure and at follow-up visits. The contraindications to the procedure were MR of Seller grade >2, left atrial (LA) thrombus on TEE performed prior to BMV, and extensive commissural calcification.

BMV was performed using the antegrade transseptal technique as previously described.20 The entry site was the right femoral vein in all patients. All procedures were done with standby facility for closed and open-heart surgery. All patients were given antibiotic cover and all were heparinized after septal dilatation. Septal puncture was done by the Brockenbrough technique. Immediately before and after BMV, the left and right heart pressures and the mean transmitral pressure gradients were measured. Left ventricular angiogram in the 30° right anterior oblique view was done prior to the procedure in all patients suspected to have more than mild MR. MR was graded 1 to 4 as described.21 Procedure success was defined as increase in mitral valve area of at least 50% from the basal or a final valve area of at least 1.5 cm2, in the absence of more than grade 2 MR.22 Restenosis was defined as loss of more than 50% of the initial gain in the mitral valve area.23

Statistical Analysis

Statistical analysis was done using SPSS version 10.0 software (IBM, Armonk, NY). Continuous variables were expressed as mean ± standard deviation. Procedural results were compared using an unpaired Student t test. For comparison of group means, a t test was used. Proportions were compared by use of the χ2 test and the Fisher exact test. P value <0.05 was considered as significant. Demographic, clinical, echocardiographic, and hemodynamic variables were tested to determine significant (P < 0.05) univariate correlates of immediate success in the AF groups.

Results

Preprocedural Clinical and Morphologic Variables

Baseline demographic and clinical characteristics of the2 groups of patients are shown in Table 1. Patients in the AF group were older, presented more frequently with NYHA functional class III, had a higher prevalence of prior surgical commissurotomy, and echocardiographic score of >8. Patients in the AF group had higher LA size (49.5 ± 6.4 mm vs 42.7 ± 6 mm, P = 0.000) and higher Wilkins echocardiography score (8.3 ± 1.3 vs 7.5 ± 1.3, P = 0.000).

Table 1. Preprocedural Clinical and Morphologic Variables
 NSRAFP
  1. Abbreviations: AF, atrial fibrillation; BMV, balloon mitral valvotomy; NSR, normal sinus rhythm; PAH, pulmonary artery hypertension; RVSP, right ventricular systolic pressure.

No.72395 
Male155 (21.4)23 (24.2)0.538
Age, y29.4 ± 10.139.9 ± 9.90.000
Height (cm)153.7 ± 10153.3 ± 9.30.067
Weight (Kg)47 ± 9.645.5 ± 90.154
Body surface area (m2)1.6 ± 4.71.4 ± 0.20.508
Pregnant patients22 (3) 4 (4.2)0.542
History of prior BMV35 (4.8)6 (6.3)0.536
History of prior surgical commissurotomy83 (11.5)32 (33.7)0.000
Functional class   
 II485 (67.1)44 (46.3)0.000
 III238 (32.9)50 (52.6) 
 IV0 (0) 1 (1.1) 
Wilkins score of >8180 (24.9)45 (47.4)0.000
Aortic valve disease292 (40.4)44 (46.3)0.269
PAH   
 No (≤30)15 (2.1)2 (2.1)0.901
 Mild (RVSP 30.1–50)329 (45.9)47 (49.5) 
 Moderate (RVSP 50.1–70)208 (29)27 (28.4) 
 Severe (RVSP >70)165 (23)19 (20) 
Left atrium (mm)42.7 ± 649.5 ± 6.40.000
Echo score7.5 ± 1.38.3 ± 1.30.000

Hemodynamic Variables Prior to BMV

Hemodynamic findings before BMV are shown in Table 2. Patients in the AF group had higher left atrial and pulmonary artery pressures (but not statistically significant) and transmitral gradient prior to the BMV (15.7 ± 5.9 mm Hg vs 13.6 ± 5.4. mm Hg, P = 0.041). The preprocedural valve area was less in the AF group.

Table 2. Hemodynamic Variables Prior to BMV
 NSRAFP
  1. Abbreviations: AF, atrial fibrillation; LA, left atrium; LA (a), Left atrial ‘a’ wave; LA (v), Left atrial ‘v’ wave; LVED, left ventricular end-diastolic pressure; MVA, mitral valve area; NSR, normal sinus rhythm; PAP, pulmonary artery pressure; TMG, transmitral gradient.

LA (a) 30.7 ± 7.7 
LA (v) 30.1 ± 10.635 ± 10.20.000
LA (mean)22.7 ± 6.823.6 ± 7.50.445
LVED9.6 ± 3.59.7 ± 3.60.710
PAP (systolic)48.6 ± 14.154.7 ± 22.20.947
PAP (diastolic)24.6 ± 8.726 ± 11.70.960
PAP (mean)33.6 ± 10.936.1 ± 150.999
TMG13.6 ± 5.415.7 ± 5.90.041
MVA0.8 ± 0.20.7 ± 0.20.804

Hemodynamic Variables After BMV

Hemodynamic findings after BMV are shown in Table 3. Patients in the AF group had higher left atrial and pulmonary artery pressures after BMV than the patients in the NSR group. The transmitral gradient was comparable between the study groups. Patients in the AF group had significantly less valve area after BMV.

Table 3. Hemodynamic Variables After BMV
 NSRAFP
  1. Abbreviations: AF, atrial fibrillation; LA, left atrium; LA (a), Left atrial ‘a’ wave; LA (v), Left atrial ‘v’ wave; LVED, left ventricular end-diastolic pressure; MVA, mitral valve area; NSR, normal sinus rhythm; PAP, pulmonary artery pressure; TMG, transmitral gradient.

LA (a) 20.2 ± 6.1
LA (v) 20.2 ± 9.123.8 ± 12.20.001
LA (mean)14.2 ± 5.615.9 ± 6.90.001
LVED12.9 ± 4.513.2 ± 4.60.179
PAP (systolic)38.9 ± 12.341 ± 16.70.947
PAP (diastolic)17.9 ± 8.519.1 ± 7.80.960
PAP (mean)26.2 ± 11.326.9 ± 11.10.999
TMG6.4 ± 4.96.9 ± 5.30.041
MVA1.6 ± 0.41.3 ± 0.40.032
Table 4. In-hospital Events
 NSRAFP
  1. Abbreviations: AF, atrial fibrillation; MR, mitral regurgitation; MVR, mitral valve replacement; NSR, normal sinus rhythm.

Success677 (93.6)80 (84.2)0.032
Peripheral thromboembolism10 (1.4)3 (3.2)0.184
Tamponade1 (0.1)2 (2.1)0.037
Stroke4 (0.6)3 (3.2)0.038
MR (≥3)56 (7.7)16 (16.8)0.005
Emergent MVR10 (1.4)3 (3.2)0.184
Death1 (0.1)0 (0) 0.884

In-hospital Events

Mitral Regurgitation: The incidence of hemodynamically significant MR was more in the AF group (16.8% vs 7.7%, P = 0.005)

Other Complications: Pericardial tamponade occurred in 3 patients (2 patients [2.1%] in the AF group and 1 patient [0.1%] in the NSR group, P = 0.037). Peripheral thromboembolic events occurred in 13 (1.6%) of the overall population: 7 (1.4%) occurred in the AF group and 3 (0.2%) in the NSR group (P = 0.184). The incidence of stroke was more in the AF group (0.6% vs 3.2%, P = 0.038).

Clinical Follow-up

Clinical follow-up information was available in 750 (91.7%) of the overall patient population at a mean follow-up time of 6.1 ± 3 years. The follow-up was completed in 83 (87.3%) of the patients in the AF group and 667 (88.9%) of the patients in the SR group.

In the AF group, cumulative events included 8 strokes, 11 mitral valve replacements, and 3 repeat BMVs, accounting for a total of 22 (26.5%) patients with combined events. Of the remaining 61 patients who were free of combined events, 53 (86.8%) were in NYHA class I or II and 8 (13.1%) patients were in class III or IV.

In the SR group, cumulative events included 3 deaths, 24 strokes, 40 MVR and 57 redo BMV, accounting for a total of 124 (18.6%) patients with combined events. Of the remaining 543 patients that were free of combined events, 480 (88.4%) were in NYHA class I or II and 63 (11.6%) patients were in class III or IV.

Discussion

The present study demonstrates that patients with rheumatic mitral stenosis with AF have a worse immediate and long-term outcome after BMV.

AF and Immediate Outcome of BMV

Patients with AF have an inferior immediate hemodynamic outcome of BMV as reflected in a lower procedural success rate (84.2% vs 93.6%, P < 0.05), higher incidence of hemodynamically significant MR, and a smaller post-BMV mitral valve area (1.3 ± 0.4 cm2 vs 1.6 ± 0.4 cm2, P = 0.032). A higher incidence of clinical and morphologic characteristics associated with suboptimal results after BMV in this patient cohort account for these results. The presence of AF was associated with higher incidence of other procedural complications such as emergent MVR, pericardial tamponade, and stroke.

AF and Long-term Follow-up After BMV

The present study also demonstrates that the presence of AF had a negative effect on the clinical follow-up of patients undergoing BMV. Therefore, the inferior immediate and long-term outcome of BMV in patients with mitral stenosis who have AF is more likely related to the presence of clinical and morphologic characteristics associated with inferior results after BMV. In the present study, patients with AF were older and presented more frequently with echocardiographic scores ≥8, NYHA functional class IV, higher mean pulmonary artery pressures, and a previous history of surgical mitral commissurotomy. Previous studies have demonstrated that older age,7,10,11,24–27 NYHA class IV at presentation,10,11,24,26,28,29 high echocardiographic score (>8),10,11,25–31 history of prior surgical commissurotomy,7,10,11,25,28,32 and fluoroscopically visible mitral valve calcification10,11,24,25,33,34 are associated with suboptimal immediate and long-term results of BMV. In addition, the worse immediate hemodynamic outcome of BMV in the AF group contributes to the worse long-term outcome of this group of patients. Smaller post-BMV mitral valve area26,27,35 and higher post-BMV pulmonary artery pressures24,26,35 have been identified as important predictors of combined events during long-term follow-up after BMV.

Comparison With Previous Studies

Poor mitral valve anatomy as suggested by echocardiographic scores ≥10 was demonstrated as a predictor of suboptimal immediate results and short-term outcome in patients with previous surgical commissurotomy.36 Similar results were shown by Hung et al,37 who reported that AF was a univariate predictor of suboptimal immediate result but not an independent predictor by multivariate analysis. Iung et al38 also identified sinus rhythm as a univariate predictor of good functional results 5 years after a successful procedure, but the multivariate analysis failed to demonstrate rhythm as a independent predictor of long-term success. Pan et al34 identified the presence of AF as an independent predictor of late success.

There were studies that did not have similar observation between AF and outcome. In the series from the National Heart, Lung, and Blood Institute registry of balloon mitral valvotomy, AF was not an independent predictor of procedural success or long-term outcome at 4 years of follow-up.26,39 Other reports also did not reveal any association between AF and suboptimal immediate or long-term outcome after percutaneous balloon valvotomy.4,5,7,27,29 The inconsistency of the results of these studies is more likely explained by the size of the patient population included in each study as well as different baseline clinical and morphologic characteristics of the patients.

Our results agree with previous surgical studies showing the negative influence of AF on the immediate and long-term outcome of patients with mitral stenosis undergoing closed and open surgical commissurotomy for the treatment of symptomatic mitral stenosis. The surgical series demonstrated that the presence of AF had an adverse effect on operative mortality and long-term survival and event-free survival after open and closed commissurotomy13–19 and was in some of them an independent predictor of outcome. In a clinical study of 1000 consecutive cases of mitral stenosis followed up to 9 years, Ellis et al17 identified the presence of NSR as an important predictor of improvement after closed surgical commissurotomy. In a study of 267 patients followed during 20 years after transventricular commissurotomy, Rihal et al18 identified AF as an independent predictor of long-term survival. In the study by Scalia et al19with a follow-up time up to 22 years after closed or open mitral commissurotomy, AF was identified as a univariate predictor of survival and effective palliation.

Similarly, we have also observed patients with AF who were sicker at the time of the balloon mitral valvotomy. They have poor immediate results when compared with the patients with NSR. They did have more events on follow-up in the form of more strokes and reinterventions.

Accordingly, AF represents a marker for more severe or long-standing mitral stenosis. Structural changes in the left atrial myocardium are important for the development of AF, and the prevalence of AF correlates with the severity of myocardial derangement in the left atrium.40–43 The strong association between age and AF in mitral stenosis suggests that the structural changes in the atrial myocardium that predispose to AF are time dependent. Therefore, the chronicity of the underlying rheumatic disease process in patients with atrial fibrillation is more likely to be associated with more severe mitral valve deformity and calcification. Therefore, it is inevitably associated with clinical and morphologic features that adversely affect the immediate and long-term outcome after BMV.

Conclusion

The present study demonstrated that the presence of AF is associated with inferior immediate and long-term outcome after BMV. Analysis of preprocedural and procedural characteristics revealed that this association is most likely explained by the presence of multiple factors in the AF group that adversely affect the immediate and long-term outcome of BMV. Therefore, the presence of AF should be a determinant in the decision process regarding treatment options in a patient with rheumatic mitral stenosis.

Study Limitations

Follow-up information was not available in 8.3% of the patient population. Because it is likely that patients may have not received follow-up due to an adverse event, this may have affected the results of our study.

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